Vehicle battery having integral safety switch

ABSTRACT

A battery having an integral emergency circuit breaker for preventing the transmission of electrical current from the battery to a vehicle in which the battery is connected in an electric circuit. The battery is connected in the circuit so its negative terminal is grounded, and its positive terminal is ungrounded, under normal conditions. The battery has an impact resistant case for shielding the contents thereof from electrical contact with the structure of the vehicle in the event of an accident. A fuse link is provided for interrupting the flow of electrical current from the positive pole of the charge storage section to the positive terminal of the battery in response to an increase in the electrical current flowing through the fuse link. The first end of the fuse link is connected to the positive pole of the charge storage section and the second end of the fuse link is connected to the exposed positive terminal. The fuse link permits the flow of current therethrough to the positive battery terminal under normal conditions. In response to perturbation of the vehicle by an accident, a switch connects the second end of the fuse link to the negative pole of the storage section so as to increase the flow of current therethrough, causing the fuse link blow and thereby interrupting the circuit.

This application is a continuation in part of Ser. No. 450,607, filedDec. 13, 1989, now U.S. Pat. No. 5.034,607.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to storage batteries in general, and, moreparticularly, to a battery for use in a vehicle and having a safetyswitch for disconnecting the battery from the electrical system of thevehicle in the event of an accident.

2. Background Art

Motor vehicle accidents, whether involving an impact, such as to thefront, rear, or side of the vehicle, or a rollover of the vehicle,frequently result in the release of flammable fuel. In the event thatthe vehicle is inverted by the accident, combustible engine oil may alsopour out of the crankcase or sump and spill into the engine compartment.Not infrequently, such spilled fuel or oil ignites, with grievousresults. Such ignition may be the result of any of a number of causes,however one common cause is the sparking of live wiring in the wreckedvehicle. Such sparking can take place not only in high voltage ignitionsystems, but may also take place elsewhere in the vehicle's wiringharness, which typically extends throughout the vehicle's body. Even ifthe engine, and thus its alternator, has ceased to operate, thevehicle's battery may continue to supply current to such circuits. Thebattery itself may also be tossed about or crushed in the enginecompartment by the force of the accident, and its live terminal(typically the positive terminal) may come into contact with themetallic bodywork of the car, creating severe sparking, much like thatof an arc Welder. Such severe sparking is able to ignite not onlyflammable fuel, but also grease and spilled oil in the enginecompartment. Because the hood is frequently crushed or otherwiseunopenable as a result of the accident, it may be impossible to gainaccess to the engine compartment to suppress such a fire.

A number of devices have been proposed in the past to cut off current inthe vehicle's electrical system in the event of an accident. U.S. Pat.No. 2,099,483, issued Nov. 16, 1937 to Hinde, discloses a circuitbreaker which is wired into the electrical system between the ignitionwiring and the ammeter. Two versions of this device are disclosed, oneof which is a mercury switch: in the event that the vehicle overturns,the mercury runs along the inside of a cylindrical casing so as toground the circuit and blow a fuse. In the second version of the device,the circuit is broken mechanically: when the device is in the verticalposition, a conical closing member bridges an insulating annulus of thelower end of a conical bore so as to close the circuit, and when thedevice is tilted to the horizontal, the circuit closer slides in thebore so as to break the circuit. Both versions, however, fail to providefor circuit breaking action in the event of a vehicular impact otherthan a rollover accident. Furthermore, they fail to eliminate the livewiring leading from the vehicle's battery up to the circuit breaker, orthe live battery post itself, either of which may cause sparking in theevent of an accident

U.S. Pat. No. 2,145,543, issued Jan. 31, 1939 to Gross, disclosesanother switch which is wired in the ignition circuit between thebattery and the ammeter. The device consists of a mercury-containingwell having two terminals therein; so long as the mercury remains in thewell, the circuit remains closed. A rod attached to the engine blockextends adjacent to the reservoir. In the event of a frontal collision,the projecting rod breaks off the well, spilling the mercury and therebycutting off the ignition. In the event that the vehicle is overturned,the mercury drains out of the top of the reservoir. The Gross device,however, also fails to eliminate either the live battery post or thelive wiring running from the battery to the switch terminal.Furthermore, it is questionable whether the arrangement would beeffective in the event of a rear or side impact.

U.S. Pat. No. 3,410,359, issued Nov. 12, 1968 to Mollison, discloses adevice which includes a moving contact mounted on a conducting bladewhich normally biases the contact against a second contact, which inturn is connected to the battery. The other end of the blade isconnected to the wiring harness In the event of a collision, a springloaded trigger is released against the blade so that the moving contactis pushed against another contact which is connected to ground, therebydisconnecting the battery from the wiring harness and grounding theharness. As with the previously described devices, the Mollison switchfails to eliminate all live wiring in a wrecked vehicle, inasmuch asboth the exposed battery posts and the wiring leading from the batteryto the circuit breaking device remain live even after the spring loadedtrigger is released. Furthermore, Mollison does not appear to teach adevice which will disconnect the electrical circuit in the event of arollover accident, as opposed to a collision.

U.S. Pat. No. 3,830,331, issued Aug. 20, 1974 to Piazza, describes adevice having a "z"-shaped male plug, one end of which is secured to theengine block, and the other end of which forms a prong which is slidablyengaged by the sleeve of a female member. The sleeve of the femalemember extends from a lead cylinder, the opposite end of which isconnected to a cable leading to the battery. When impact occurs, theinertia of the heavy lead weight on the female member causes it to moveforward and disengage the sleeve from the prong of the male plug. Again,this device fails to completely eliminate the exposed battery posts andthe possibility of live wiring in the wrecked vehicle; furthermore, thePiazza device would not appear to disconnect the electrical system inthe event of a rollover accident, or a side or rear-end collision.

Accordingly, there exists a need for a device to effectively disconnectthe wiring of a vehicle from the battery in the event of a front orrearend collision or a rollover accident so as to eliminate allpossibility of live wiring in the vehicle, as well as for a device whichwill prevent live battery terminals or posts from coming into contactwith the vehicle structure in such an accident and causing sparks whichmay ignite a fire.

SUMMARY OF THE INVENTION

The present invention, in its broadest sense, resides in an emergencycircuit breaker for preventing the transmission of electrical current toa vehicle from a battery connected in an electric circuit of thevehicle. The battery is connected in the circuit of the vehicle so thatat least one terminal is not grounded under normal conditions. Thecircuit breaker has impact resistant means for shielding the ungroundedterminal of the battery from electrical contact with the structure ofthe vehicle. Fuse means are provided for interrupting the flow ofcurrent from the battery to the vehicle circuit in response to apredetermined increase in the current flowing through the fuse means.Means are provided for connecting the ungrounded terminal of the batteryto a first side of the fuse means, and impact resistant means areprovided for shielding the electrical connecting means from contact withthe structure of the vehicle. Switch means are provided for connecting asecond side of the fuse means to ground in response to perturbation ofthe vehicle by an accident. Accordingly, in the event of an accident,such perturbation causes the switch means to electrically connect thesecond side of the fuse means to ground, thus increasing the flow ofcurrent through the fuse means so that the fuse means interrupts thecircuit, and the ungrounded terminal of the battery and the meansconnecting the ungrounded terminal to the fuse means are shielded fromcontact with the structure of the vehicle in the event of impacttherewith as a result of the accident.

In a preferred embodiment, there is a battery having an integralemergency circuit breaker. The battery comprises an impact resistantinsulating case for shielding its contents from electrical contact withthe structure of the vehicle in the event of an accident. A chargestorage section is enclosed within the case, and has first and secondpoles. A first terminal is provided which has an end which is exposed atthe surface of the case, and which is normally connected to ground, thefirst terminal being connected to the first pole of the charge storagesection. A second terminal is provided which has an end which is exposedat the surface of the case, and which is normally ungrounded. A fuselink is enclosed within the case and has a first end which is connectedto the second pole of the storage section, and a second end which isconnected to the second terminal. The fuse link is adapted to interruptthe flow of current therethrough in response to an increase in thecurrent. There are switch means in electrical contact with the secondend of the fuse link, the switch means being enclosed within the caseand being adapted to electrically connect the second end of the fuselink to ground in response to perturbation of the vehicle by an accidentThe ground may be the first pole of the charge storage section.

The switch means may comprise an impact switch and a rollover switch.The impact switch comprises a cylindrical bore having its axis alignedin a longitudinal direction with respect to the a normal direction ofmotion of the vehicle. First and second electrical contacts protrudelaterally into the bore to form a contact gap intermediate the first andsecond ends thereof. The first contact is connected to the second end ofthe fuse link, and the second contact is connected to ground. A firstferrous ball is disposed in the bore intermediate the first end thereofand the contact gap, and is sized to bridge the gap in the event that itmoves into contact with the first and second contacts. A second ferrousball is similarly disposed in the bore intermediate the second endthereof and the contact gap. A first magnetic cup is mounted in thefirst end of the bore for retaining the first ferrous ball at a spaceddistance from the contact gap under normal conditions and is adapted torelease the ball to move into contact with the first and second contactsin the event of an impact imparted to the vehicle in a firstlongitudinal direction. A second magnetic cup is similarly mounted inthe second end of the bore for retaining the second ball apart from thecontact gap until the ball is released to move into contact with thefirst and second contact in response to an impact in a secondlongitudinal direction.

The rollover switch comprises a vertically elongated opening in thehousing, in which are mounted third and fourth electrical contacts whichform a contact gap, the third contact being connected to the second endof the fuse link and the fourth contact being connected to ground. Athird ferrous ball is disposed in the vertically elongate opening, andis adapted to close the contact gap in the event that it moves intocontact with the third and fourth contacts third magnetic cup is mountedin the opening to retain the ball a spaced apart: distance insubstantially vertical alignment below the contact gap under normalconditions, and is adapted to release the ball to move into contact withthe third and fourth contacts in the event that the vehicle is invertedby an accident.

The switch means may also comprise a side impact switch. The side impactswitch comprises a cylindrical bore having its axis aligned in a lateraldirection with respect to a normal direction of motion of the vehicle.Similarly to the longitudinal impact switch, the side impact switch isprovided with first and second electrical contacts which form a gapacross the bore between its first and second ends. The first contact isconnected to the second end of the fuse link and the second contact isconnected to ground. A first ferrous ball is retained in a magnetic cupat a first end of the bore, and a second ferrous ball is retained in asecond magnetic cup at a second end of the bore. Each magnetic cup isadapted to release its ferrous ball to move along the bore and intocontact with the first and second contacts in the event of an impactimparted to the vehicle in a selected lateral direction. Each ferrousball is adapted to close the gap between the contacts in the event whenit moves into contact therewith.

In another embodiment, the switch means may comprise a chamber having abowl-shaped lower portion with a substantially circular upper rim, and aclosed upper portion. First and second contact rings are mountedcircumferentially about the rim of the chamber, so that a gap is formedbetween the contact rings, the first contact ring being connected to thesecond end of the fuse link and the second contact ring being connectedto ground. A ferrous ball is disposed in the chamber and is adapted toclose the gap between the contact rings in the event that it moves intocontact therewith. A magnetic cup is mounted proximate the center of thelower portion of the chamber to retain the ball at a spaced distancefrom the contact gap under normal conditions, the cup being adapted torelease the ferrous ba)1 in response to an impact to, or inversion of,the vehicle by an accident, so that the ball moves into contact with thecontact rings. A magnetic belt may be mounted about the rim forsubsequently retaining the ferrous ball in contact with the contactrings.

Other features of the present invention will become apparent from thefollowing detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a circuit breaker incorporating the presentinvention, with a portion cut away to reveal internal componentsthereof;

FIG. 2 is a side sectional view of the circuit breaker of FIG. i takenalong line 2--2;

FIG. 3 is a side sectional view of the circuit breaker of FIG. 1 takenalong line 3--3;

FIG. 4 is a perspective view of a conventional vehicle battery havingthe circuit breaker of FIG. 1 mounted thereon;

FIG. 5A is a diagrammatical representation of another embodiment ofcircuit breaker incorporating the present invention, this being mountedon a conventional vehicle battery having flush-type side post terminals;

FIG. 5B is another diagrammatical representation of the side postbattery of FIG. 4A, having another embodiment of circuit breakerincorporating the present invention mounted thereon:

FIG. 6 is a diagrammatical representation of a battery having anintegral circuit breaker switch in accordance with the presentinvention;

F1G. 7 is a sectional view of another embodiment of a switch for use ina circuit breaker in accordance with the present invention.

FIG. 8 is a sectional view of the battery of FIG. 6, taken along line8--8, showing the integral circuit breaker switch mounted therein, thisbeing similar to the switch mechanism shown in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

In its preferred embodiment, the present invention comprises a batteryhaving a circuit breaker mounted integrally within the case of thebattery. In the interest of clarity, however, this description willbegin with a discussion of an embodiment of the invention in which aseparate circuit breaker assembly is mounted on a conventional battery.

FIG. 1 shows an emergency circuit breaker assembly)y 10 in accordancewith the present invention. Assembly 10 is adapted to be mounted to thatterminal of a battery which is not grounded to the structure of thevehicle under normal conditions. As used in this description and theappended claims, the term "structure" of the vehicle refers generally tothe bodywork thereof, including the body panels, frame, engine block,etc., which are typically composed of metallic, electrically conductivematerial, and which are typical)y interconnected in non-insulatingcontact with one another. In many vehicles, such as typical automobiles,trucks, buses, motorcycles, and the like, the structure of the vehicleserves as a common ground which forms one side of the circuit.

Thus, one post or terminal of the battery, typically the negativeterminal, is grounded to the vehicle structure under normal conditions.The other terminal of the battery, typically the positive terminal, isungrounded under normal conditions, and is instead connected to thewiring harness which supplies current to a variety of components.Accordingly, it will be understood that the normal current flow from thepositive pole of the battery, because it must pass through the wiringharness and the resistance of the components in order to reach theground side of the circuit, is significantly less than it would be ifthe positive pole of the battery were to be connected directly to groundthrough minimum resistance. In other words, if the positive terminal ofa typical battery were, in the event of an emergency, to be connecteddirectly to ground, the flow of current from the positive terminal)through the means connecting that terminal to ground would besignificantly greater than that flowing from the positive terminal tothe wiring harness under normal conditions.

It may be noted at this point that the term "normal conditions", "normalcircumstances", etc., as used in this description and the appendedclaims, refer both to the normal, relatively undamaged structure,electrical circuit, battery, etc., of the vehicle, as well as to thenormal operating modes of the vehicle, in which the forces (e g.,bouncing, jarring, centripetal forces, etc.) which are associated withthe normal operation of the vehicle act upon the components mountedthereto. By contrast, the term "accident" refers to an event, such as acollision or a rollover, which results in perturbation of the vehicle,and which generally causes damage to the structure of the vehicle andwhich may cause spillage or leakage of fuel or other flammable)ematerials. Furthermore, the term "perturbation" refers to the action ofgreatly disturbing the vehicle or other object physically, so as tounsettle, derange, and throw the components thereof into confusion. Asnoted above, such perturbation may cause fuel leaks, damage wiringharness insulation, toss the battery about the engine compartment sothat its ungrounded terminals contact the vehicle structure, and soforth, and thus create a severe fire hazard.

With further reference to FIG. 1, it will be seen that circuit breakerassembly 10 is provided with a housing 12, which serves not only as asupport structure for the internal components of assembly 10, but alsoserves as an impact resistant casing for shielding the ungroundedterminal of the battery and the internal components of circuit breakerassembly 10 from electrical contact with the structure of the vehicle.Accordingly, housing 12 is constructed of a material which exhibits bothgood insulating qualities and high impact resistance, for example, highimpact plastic or hard rubber. Housing 12 preferably completelysurrounds and shields the portion of the positive battery post which isexposed at, or which protrudes from, the surface of the case of thebattery, as well as the internal components of the circuit breakerassembly.

Within housing 12 there is mounted a battery post receptacle 14 forreceiving a typical positive battery post. Receptacle 14 is preferablyprovided with internal vertical fluting or teeth 15 which cut into andgrip the battery post so as to establish good electrical contact betweenthe post and receptacle. While many typical battery posts or terminalsprotrude outwardly from the battery casing so as to be gripped by acable clamp, some conventional batteries have relatively flush posts orterminals which are tapped to receive a bolt on a flush-fitting cableconnector. Accordingly, it will be understood that receptacle 14 mayeither be a recessed receptacle for receiving a conventional protrudingbattery post, as shown in FIG. I, or a flush fitting receptacle formounting against a flush mount battery post. Receptacle 14 may beprovided with a pair of set screws 16, which are threadably engaged withlateral bores which penetrate into the interior of receptacle 14 so thatthe set screws can bear directly against the post when it is received inthe receptacle, thereby securing circuit breaker assembly 10 to thebattery post Alternatively, as shown in FIG. 1, the set screws 16 may bethreadably engaged with bores formed in housing 12 so as to bear againstthe exterior surface of battery post receptacle 14, so that when theyare tightened they force the material of the receptacle against thebattery post. Receptacle 14 itself is composed of a suitable conductivematerial, such as lead or copper.

The upper end of receptacle 14 preferably abuts against a solid plug 17of insulating material plug 17 is preferably formed as part of housing12, and provides a surface on which a person can tap with a hammer wheninstalling circuit breaker assembly 10, so as to drive battery postreceptacle 14 down onto the battery post, with the internal teeth 15cutting into the surface of the battery post. Plug 17 may be providedwith a legend 18, such as a red dot bearing a "+" sign, to indicate theproper terminal of the battery for installation of the circuit breakerassembly.

Electrical connector 19, which may be a separate electrical conductor,such as a wire, or, as is shown in FIG. 1, an extension of theconducting material of receptacle 14, connects receptacle 14 to thefirst end 22 of fuse link 20. The first and second ends 22, 24 of fuselink 20 are mounted in fuse clips 26. Fuse link 20 permits the flow ofcurrent therethrough from its first end to its second end under normalconditions, such as the normal loads associated with the starting andoperation of the Vehicle. Fuse link 20 is, however, adapted to interruptthe flow of current therethrough in response to a significant,predetermined increase in such flow, as would result if the current wereto flow directly from the positive battery terminal through fuse link 20to ground Fuse link 20 may be any suitable form of fuse known to thoseskilled in the art, such as a fuse having metallic wires or strips whichmelt under excessive current loads, or may be, as another example, asolenoid activated trip-type circuit breaker. Furthermore, it will beunderstood that, while the fuse link 20 in FIG. 1 is shown connected incircuit breaker assembly 10 so as to carry (and hence directlyinterrupt) the entire flow of current from the battery to the wiringharness, the circuit breaker may be equally effective in an arrangementwherein the fuse link is connected in a secondary circuit between thepositive battery post and switch means (which will be described below),and wherein fuse link 20 serves to activate other circuit-interruptingmeans in the main circuit leading from the positive battery post to thevehicle wiring harness. In such an alternative arrangement, impactresistance insulating shielding would be provided for the portion of themain circuit which would run between the battery post andcircuit-interrupting means.

In the embodiment shown in FIG. 1, the second end 24 of fuse link 20 isconnected by electrical connector 28 to cable post 30. As withelectrical connector 19 described above, electrical connector 28 mayeither be a separate electrical connector or an extension of thematerial of cable post 30. Cable post 30 is preferably formed of asuitable conductive material, such as, for example, lead or copper, andhas an outer end 32 which protrudes from housing 12 to provide asuitable attachment point for a conventional battery cable connected tothe vehicle's wiring harness.

Connected via connector 28 to the second end of fuse link 20 is arollover switch 40, which is set in an opening or chamber 41 formed inhousing 12. Rollover switch 40 comprises a pair of electrical contacts42 and 44, which are fabricated of a suitable conductive material, andwhich are positioned and spaced apart from one another so as to form anelectrical contact gap within chamber 42. Contact 42 is connected byconnectors 46 and 28 to second end 24 of fuse link 20, and contact 44,in turn, is connected by connector 48 to ground 50, which may be theframe, engine block, or other part of the vehicle structure. Ground 50may also be, as will be discussed below, the other (i.e., the negative)terminal of the battery. Rollover switch 40 further comprises a closingmember 52 which is mounted in chamber 42 so that it is free to movevertically therein. Closing member 52 is adapted to close the gapbetween contacts 42 and 44 in the event that it comes into contacttherewith. Electrical closing member 52 may, for example, be a mass ofmercury or a ball of electrically conductive solid metal, such as aferrous ball having a suitable diameter to bridge the gap between thecontacts. As used in this description and the appended claims, the term"ferrous" refers to a material having iron or an iron compound therein,such as steel, so that such material is both electrically conductive andattracted by magnetic forces. It will be understood that otherparamagnetic materials are available for use in the present inventionwhich also exhibit conductive qualities, such as nickel, although suchmaterials are typically more expensive than ferrous materials. Closingmember 52 rests in a cup 54 under normal conditions. If closing member52 is a ferrous ball, cup 54 is preferably a magnetic cup having acorresponding concave interior surface. Cup 54 is arranged to retainclosing member 52 a vertically, spaced apart distance below the contactgap under normal conditions. However, in the event that the vehicle isinverted by an accident, cup 54 is adapted to release closing member 52so that the latter moves vertically to come into contact with electricalcontacts 42 and 44, thereby completing the connection between the secondend of fuse link 20 and ground 50. If closing member 52 is a mass ofmercury, it will simply flow under the influence of gravity into contactwith contacts 42 and 44 if the vehicle is inverted; if closing member 52is a ferrous ball and cup 54 is a magnetic cup, then the mass of ferrousball 52 and the magnetic force of cup 54 are selected so that the ballwill be released from the cup and fall vertically into contact withcontacts 42 and 44. The resulting increase in current flowing throughfuse link 20 will, in turn, cause the fuse link to "blow", therebyimmediately interrupting the flow of current from the battery to thewiring harness, and eliminating the possibility of live wiring in thevehicle which might cause sparking. Furthermore, impact resistantinsulating housing 12 will prevent the positive battery post from cominginto contact with the vehicle structure (e.g., the interior of theengine compartment) in the event that the battery is dislodged and fallsdue to the inversion of the vehicle.

Circuit breaker assembly 10 also includes a longitudinal impact switch60, which is positioned in housing 12 laterally opposite rollover switch40, thus providing a compact and sturdy arrangement. Longitudinal impactswitch 60 comprises a substantially cylindrical bore 62 in theinsulating material of housing 12, the longitudinal axis of which isadapted to be aligned with the normal direction of motion of the vehiclewhen the circuit breaker assembly is mounted on the battery. First andsecond electrical contacts 64 and 66 penetrate bore 62 laterally to forma contact gap at a point intermediate the first and second ends of bore62. First contact 64 is connected by connectors 68 and 28 to the secondend 24 of fuse link 20, and contact 66 is connected by connector 72 toground 74. Ground 74 may be, as previously described, the structure ofthe vehicle or the other pole of the battery. A first circuit closingmember, which is preferably a suitably sized ferrous ball 76 similar tothat described above, is disposed in bore 62 intermediate a first end ofthe bore and the contact gap, so that the ball is free to movelongitudinally therethrough. A second ferrous ball 78 is similarlydisposed in bore 62 intermediate the second end thereof and the contactgap. First and second ferrous balls 76 and 78 are each adapted to closethe gap between contacts 64 and 66 in the event that they move intocontact therewith, so as to thereby complete the electrical connectionbetween the second end of fuse link 20 and ground 74.

A magnetic holding cup 80 is mounted in the first end of bore 62, andhas an inner face which receives first ferrous ball 76. The mass offerrous ball 76 and the magnetic force of cup 80 are selected such thatan impact of predetermined magnitude imparted to the vehicle in theapplicable longitudinal direction will cause first ferrous ball 76 toseparate from magnetic cup 80 due to the inertia of ball 76. Followingseparation, the inertia of ferrous ball 76 will carry it through bore 62until it comes into contact with contacts 64 and 66, in the positionindicated by broken line image 81. The electrical connection between thesecond end of fuse link 20 and ground 74 is thus completed, and theresulting increase in current flowing through fuse 20 link causes it tointerrupt the circuit in the manner previously described. Second ferrousball 78 is similarly retained in the second end of bore 62 by secondmagnetic cup 82.

If, for illustrative purposes, it is assumed that the normal directionof forward motion of the vehicle is to the left in FIG. 2, it will beseen that first ferrous ball 76 and first magnetic cup 80 will beresponsive to opposing impacts received at the forward end of thevehicle, which would result in ferrous ball 76 moving to the leftthrough bore 62, while second ferrous ball 78 and second magnetic cup 82will be responsive to opposing impacts at the rear end of the vehicle.Inasmuch as rear-end impacts are typically less severe than front endimpacts, it may be desirable, in this example, to either increase themass of second ball 78 or decrease the magnetic force of second cup 82(relative to the first bal) and cup, which need to resist separationunder normal braking forces), so as to make it relatively easier forsecond ferrous ball 78 to separate from cup 82.

FIG. 1 also shows a lateral impact switch 90, which is similar inconstruction and operation to longitudinal impact switch 60, with theexception that the lateral impact switch is oriented with its axissubstantially perpendicular to the normal direction of motion of thevehicle. Accordingly, lateral impact switch 90 comprises a substantiallycylindrical bore 92 in the insulating material of housing 12, into whichfirst and second electrical contacts 94 and 96 penetrate laterally toform a contact gap at a point intermediate the first and second ends ofthe bore First contact 94 is connected by electrical connectors 98 and28 to second end 24 of fuse link 20, while contact 96 is connected byconnectors 100 and 102 to ground 104.

A first ferrous ball 106 is disposed in bore 92 intermediate the firstend of the bore and the contact gap so that it is free to movelongitudinally through the bore. Similarly, second ferrous ball 108 isdisposed in bore 92 intermediate the second end of the bore and thecontact gap. First and second ferrous balls 106 and 108 are each adaptedto close the contact gap in the event that they move into contacttherewith, thereby completing an electrical connection between thesecond end of the fuse link and ground. A first magnetic holding cup 112is mounted in the first end of bore 92 and has a concave inner facewhich receives ferrous ball 106. Similarly, a second magnetic cup 112 ismounted in the second end of bore 92 and retains a second ferrous ball108. The mass of each ball and the magnetic force of its associated cupare selected so that an impact of a predetermined magnitude which isimparted to the vehicle in the applicable lateral direction will resultin the separation of the ball from the cup. Following separation, theinertia of the ball will carry it through bore 92 until it comes intocontact with contacts 94 and 96, as in the position indicated by brokenline image 114, thus completing the connection between the second end offuse link 20 and ground 104, and causing fuse link 20 to interrupt thecircuit in the manner previously described.

It will be understood by those skilled in the art that other forms ofswitches which are responsive to impact and/or inversion, such as otherforms of inertia-sensing switches, may be substituted for theabove-described embodiments of the rollover switch, longitudinal impactswitch, and lateral impact switch in the circuit breaker assembly of thepresent invention.

FIG. 2 shows side view of circuit breaker assembly 10, in which batterypost receptacle 14 is seen secured to a positive battery post 116 whichprotrudes above casing 122 of battery 120. Housing 12 fits closelyagainst casing 122, and a bead 124 of sealant is provided at the outerjoint where these meet, providing a weatherproof seal which preventscorrosion of both battery post 116 and the internal components ofcircuit breaker assembly 10. Fuse link 20 shown in FIGS. 1-2 is areplaceable fuse, such as a conventional cartridge-type orautomotive-type fuse, and, accordingly a door 118 is provided in housing12 to permit access for the removal and replacement of the fuse link.Fuse clips 26 permit easy engagement and disengagement of fuse link 20,and provide effective electrical contact with the ends thereof.

FIG. 3 shows vertically extending chamber 41 of the roll-over switchwhich is formed within housing 12. Ferrous ball 52 is mounted forvertical movement within chamber 41, and is retained by magnetic cup 54a spaced distance below the gap between contacts 42 and 44 under normalconditions. Upon inversion of the vehicle by an accident, however, cup54 releases ball 52, which moves vertically into contact with contacts42 and 44 in the position indicated by broken line image 126, closingthe gap between the contacts and thereby causing the fuse link tointerrupt the flow of current to the vehicle's wiring harness.

FIG. 4 shows a perspective view of the circuit breaker assembly 10 ofFIGS. 1-3 mounted on conventional battery 120. Negative battery post 128protrudes from the insulating case 122 of the battery, and is typicallyconnected to ground by a grounding strap running to the engine block orother part of the vehicle structure. It will be observed that theprotruding portion of the positive battery post is completely surroundedby impact resistant insulating housing 12. The cable post end 32, whichin turn protrudes from housing of circuit breaker assembly 10, providesa suitable attachment point for the battery cable leading to thevehicle's wiring harness, which cable would in a conventionalinstallation be attached directly to the positive post of the battery.

FIG. 5A shows a diagrammatical view of another embodiment of circuitbreaker in accordance with the present invention, this being mounted onconventional sidepost-type battery 130 having a case 132 and asubstantially flush positive post or terminal 134. Flush terminal 134 isprovided with a tapped central bore 136 which, when connected in aconventional manner, receives the central bolt of a flush fittingbattery cable connector. In this embodiment of the invention, circuitbreaker assembly 140 is mounted to the side of battery 130 so as toenclose terminal 134. Assembly 140 has a battery post receptacle which,rather than receiving a protruding battery post as described above, hasa face (not shown) which fits flushly against side terminal 134. Acentral bolt (not shown) passes through the flush fitting face of thebattery post receptacle and threads into tapped bore 136, so as tosecure circuit breaker assembly 140 against the side of battery 130.Circuit breaker assembly 140 is likewise provided with a flush mounttype cable post or terminal 142, which corresponds to cable post 32described above, and which is penetrated by a tapped central bore 144for attachment of the flush mounting battery cable. Apart from thejust-described features relating to the attachment of the assembly tothe side terminal-type battery, circuit breaker assembly 140 issubstantially similar in construction and operation to that describedabove with reference to FIGS. 1-3. FIG. 5B shows a diagrammatical viewof a circuit breaker 145 which is very similar to that shown in FIG. 5A,and which also mounts to the side post-type battery 130. Circuit breakerassembly 145 mounts to the side post terminal 134 in the mannerdescribed above, and accordingly has a substantially flush cable post146 having a tapped central bore 147. Circuit breaker assembly 145differs from that shown in FIG. 5A in that assembly 145 is provided witha horizontally elongate housing portion 148 which serves to provideadditional space in which to enclose longitudinal and/or lateral impactswitches, such as those described above.

The foregoing discussion has focused on circuit breaker assemblies whichare suitable for mounting on the exterior of conventional vehiclebatteries; this provides a suitable assembly which can be purchasedseparately from the conventional battery and installed by safetyconscious vehicle owners, dealers, or manufacturers. Desirably, however,a newly manufactured battery may be provided which incorporates such acircuit breaker as an integral part thereof. Accordingly, FIG. 6 shows ablock diagram of a battery 150 having an impact resistant insulatingcase 151 for shielding its contents from electrical contact with thestructure of the vehicle in the event of perturbation of the vehicle byan accident. Battery 150 has a conventional charge storage section 152which is enclosed within insulating case 151 and which has first andsecond poles 153 and 154, the first pole being the negative pole and thesecond pole being the positive pole. Battery 150 has an exposed negativeterminal 156, which may be a protruding battery post, as shown, or aflush-mount side terminal as previously described, and which isconnected by electrical connector 160 to the negative pole 153 of chargestorage section 154; similarly, an exposed positive terminal 158 is alsoprovided. Negative terminal 156 is normally grounded to the structure ofthe vehicle and positive terminal 158 is normally connected to thewiring harness.

A circuit breaker assembly 162, such as that described above, isenclosed within case 152. As was previously described, assembly 164 isprovided with a fuse link and switch means (not shown in FIG. 6). Thefirst end of the fuse link is connected to positive pole 154 of chargestorage section 152 by connector 164, and the second end of the fuselink is connected to positive battery terminal 158 by connector 166. Theswitch means, which may be the combination of rollover and longitudinaland lateral impact switches previously described, is enclosed withinbattery case 152, and is also connected to the second end of the fuselink. The switch means is adapted to connect the second end of the fuselink to ground in response to perturbation of the vehicle by anaccident, and in the arrangement shown, the switch means is configuredto connect the second end of the fuse link to the ground provided by theother (negative) terminal of the battery or the negative pole of thecharge storage section. Accordingly, connector 168, such as a wire, isenclosed within the case of the battery and connects the switch to thenegative pole 153 of charge storage section 152 via connector 160. Inthe event of perturbation of the vehicle by an accident, the resultingvery large flow of current from the positive pole of the storage sectionto the negative pole of the storage section through the fuse link causesthe fuse link to interrupt the circuit from the positive pole of thestorage section to the exposed positive terminal of the battery.

FIG. 8 shows an overhead view of circuit breaker assembly 162 withinbattery case 152. Inasmuch as the internal structure and switches ofassembly 162 are substantially similar to those of circuit breakerassembly 10, as described above, like reference numerals will be used todesignate like structures in describing assembly 162. Circuit breakerassembly 162 includes a housing 192 which excludes the liquidelectrolyte of the battery from the internal components of assembly 162;inasmuch as assembly 162 is mounted within the impact-resistant case 152of battery 150, the housing itself may or may not be constructed of animpact-resistant material. Mounted within housing 192 is a fuse link 20having first and second ends 22 and 24 mounted in fuse clips 26. Asdiscussed above, fuse link 20 permits the flow of current therethroughunder normal conditions, and interrupts the flow of current therethroughin response to a predetermined increase in that flow. The first end 22of fuse link 20 is connected through connectors 19 and 164 to thepositive pole 154 of the charge storage section of battery 150, and thesecond end 24 of the fuse link is connected via connector 28 toconnector 166, which extends to the exterior of case 151 and isconnected to the protruding positive post 158 (not shown in FIG. 8) ofbattery 150, as described above. Accordingly, under normal conditions,the flow of current is from positive pole 154 of the charge storagesection, through connectors 164 and 19 to fuse link 20, and from fuselink 20 through connectors 28 and 166 to positive battery post 158,which is connected to the vehicle's electrical system.

Also connected to the second end of fuse link 20, through connectors 28and 46, is a roll-over switch 40. As was described above, roll-overswitch 40 comprises a chamber 41 which encloses a pair of contacts 42and 44, contact 42 being connected to connector 46 and contact 44 beingconnected to connector 48, and a closing member 52 which is normally isretained below the gap between the contacts by magnetic cup 54; in theevent that the vehicle is inverted, closing member 52 is released by thecup and closes the contact gap, completing the circuit from the secondend of fuse link 20 to connector 48 Connector 48, in turn, is connectedvia connector 196 to connector 168, which, as previously described, isconnected to the negative pole 153 of the charge storage section ofbattery 150. Accordingly, in the event that the vehicle is inverted byan accident, the resulting increase in current flowing through fuse link20, from pole 154 to pole 153, causes the fuse link to interrupt &heflow of current therethrough from the storage section to the wiringharness which is attached at post 158. In similar fashion, longitudinaland lateral impact switches are also provided within housing 162.Longitudinal impact switch 60, as previously described, comprises alongitudinal bore 62 which is aligned with the normal direction ofmotion of the vehicle, while the bore 92 of lateral impact switch 90extends in a transverse direction relative to the normal direction ofmotion of the vehicle. In many vehicles, battery 150 will be mounted, asshown, with the long axis of the battery case aligned with thelongitudinal direction of the vehicle)e; in other cases, the batterywill be mounted so that the long axis of the battery case is transverseto the longitudinal axis of the vehicle, and, in this case, thelongitudinal impact switch 60 will instead serve as a lateral impactswitch, while the lateral impact switch 90 will serve as a longitudinalimpact switch.

As described above, longitudinal impact switch 60 has first and secondelectrical contacts 64 and 66 which form a gap in bore 62, contact 64being connected through connectors 68 and 28 to the second end of fuselink 20, and contact 66 being connected, in this case, through connector70, in this case, to the first end of electrical connector 202, thesecond end of which is connected through connector 168 to the negativepole 153 of the charge storage section of battery 150. As previouslydescribed, in the event of a longitudinal impact, either one or theother of the closing members 76, 78 will disengage from its respectiveretaining cup 80, 82 at an end of bore 62, and will travel to aposition, as indicated by broken line image 81, in which the closingmember closes the contact gap and completes the circuit from thepositive pole of the charge storage section through fuse link 20 to thenegative pole of the charge storage section, thus causing fuse link 20to blow. Lateral impact switch 90, in turn, comprises first and secondcontacts 94 and 96, which form a contact gap across bore 92, contact 94being connected to the second end of fuse link 20 via connectors 98 and28, and contact 96 being connected via connectors 100 and 168 to thenegative pole 153 of the charge storage section of battery 150. Aspreviously described, in response to a lateral impact, one or the otherof the closing members 106, 108 is released from its respective magneticcup 110, 112, and travels into contact with and closes the contact gap,as indicated by broken line image 114, completing the circuit from thepositive pole of the charge storage section through fuse link 20 to thenegative pole of the charge storage section, causing fuse link 20 toblow.

Accordingly, it will be appreciated that the circuit breaker assembly162 of the battery 150 shown in FIG. 8 is substantially similar to thecircuit breaker assembly 10 of FIG. 1, differing primarily in that (a)it is enclosed within the impact-resistant insulating case 152 ofbattery 150. (b) rather than having a separate cable post connected toelectrical connector 28, connector 28 is connected through connector166, to the positive post 158 of the battery, and (c) the secondcontacts 48, 70, and 96 of the roll-over, longitudinal impact, andlateral impact switches, respectively, are connected to the negativepole of the charge storage section of battery 150, rather than to theground provided by the bodywork of the vehicle.

In an arrangement similar to previously-described access door 118, anaccess door may be provided in battery case 151 for removal andreplacement of the fuse link in circuit breaker assembly 162.

FIG. 7 shows another embodiment of switch means for use in the circuitbreaker of the present invention, and, in particular, shows circularswitch assembly 170 which is responsive to impacts imparted to thevehicle in any generally horizontal direction, as well as to rollover ofthe vehicle. Switch assembly 170 Is preferably hemispherical in overallshape, and has a bowl-shaped lower portion, or bowl, 172. While abowl-shaped lower portion may be preferable for helping retain theclosing member of the switch in the desired position during normaloperation of the vehicle, it will be understood that in someapplications, the lower portion of switch assembly 170 may notnecessarily be bowl shaped; for example, a generally flat, circularlower portion may be desirable in some applications. proximate thecenter of bowl 172 is mounted magnetic cup 174. Magnetic cup 174, in amanner similar to the magnetic cups previously described, has aninterior surface which is concave for receiving and retaining a ferrousball 176 closing member under normal conditions. The mass of ball 176and the magnetic force of cup 174 are such, however, that ferrous ball176 will be freed to move about the interior of switch assembly 170 inthe event that the vehicle suffers an impact or rollover due to anaccident.

Bowl 172 has a circular upper edge, about which are circumferentiallymounted first and second electrical contact rings 17S and 180. First andsecond contact rings 17S and 180 are exposed at the interior surface ofassembly 170, and are spaced apart from one another to form a contactgap. Ferrous ball 176 is sized to bridge the gap between the first andsecond contact rings, and is maintained at a spaced apart distance fromthe contact gap under normal conditions by magnetic cup 174. Firstcontact ring 178 is connected to first connector 182, and second contactring 180 is connected to second connector 184. In thepreviously-described manner, one of the connectors 182 or 184 iselectrically connected to the second side of the fuse link of thecircuit breaker, while the other connector is connected to ground.Accordingly, in the event that ferrous ball 176 is dislodged by anaccident and comes into contact with contact rings 178 and 180, anelectrical circuit between the second end of the fuse link and groundwill be completed, thus causing the fuse link to blow.

Contact rings 178 and 180 may preferably be mounted to the inner surfaceof a magnetic belt 186. Magnetic belt 186 preferably has a concave innersurface which is configured to receive ferrous ball 176 when it comesinto contact with rings 178 and 180, so that ferrous ball 176 isretained in that position to keep the circuit closed. Inasmuch asmagnetic belt 186 may be fabricated from an electrically conductivemagnetic material, contact rings 178 and 180 are each preferably mountedto magnetic belt 186 in an insulating channel 188, which may beconstructed of any suitable insulating material, so as to avoidelectrical contact between the contact rings and the magnetic belt.

The upper portion of switch assembly 170 is closed by a cap 190 toprevent the escape of ball 176 from the interior of switch assembly 170,so that, once separated from magnetic cup 174 by an accident, the ballretained within assembly 170 so that it comes into contact with thecontact rings. Cap 190 may preferably be provided with a convex innersurface, so that if ferrous ball 176 is dislodged from magnetic cup 174by an inversion of the vehicle and falls into contact with cap 190, itwill roll off of inner surface of cap 190 towards the circumferencethereof, and thus be directed into contact with contact rings 178 and180. Furthermore, cap 190 may preferably be detachable to provide accessto the interior of circular switch assembly 170, so that ferrous ball176 can be manually removed from contact rings and replaced in magneticcap 174 to reset switch assembly 170 following an accident.

lt will be understood from the foregoing description that the circularswitch assembly 170 is responsive to impacts imparted in any generallyhorizontal direction by an accident, as well as to rollover of thevehicle. Accordingly, in some embodiments of the present invention, thecircular switch assembly 170 may be installed in a circuit breakerassembly in place of the separate longitudinal impact, lateral impact,and rollover switches previously described. Furthermore, other suitableinertia-sensing switch mechanisms may be similarly used in a circuitbreaker of the present invention.

lt is to be recognized that these and various other modifications couldbe made to the illustrative embodiments without departing from thespirit and scope of the present invention. Accordingly, the invention isnot to be limited except as by the appended claims.

What is claimed and desired to be secured by Letters Patent of theUnited States is:
 1. A battery having an integral emergency circuitbreaker for preventing the transmission of electrical current from saidbattery to a vehicle which has said battery connected to an electricalcircuit of said vehicle, said battery comprising:an impact-resistantinsulating battery case for shielding contents of said battery case fromelectrical contact with the structure of said vehicle in the event ofperturbation of said vehicle by an accident; a charge storage sectionenclosed within said battery case, said charge storage section having afirst pole and a second pole; a first terminal having an end exposed ata surface of said battery case, said first terminal being electricallyconnected to said first pole of said charge storage section, said firstterminal further being connected to said electrical circuit of saidvehicle so that said first terminal is grounded to the structure of saidvehicle under normal conditions; a second terminal having an end exposedat a surface of said battery case, said second terminal beingelectrically connected to said second pole of said charge storagesection, said second terminal further being connected to said electricalcircuit of said vehicle so that said second terminal is ungrounded undernormal conditions; fuse means enclosed within said battery case forinterrupting a flow of electrical current from said second pole of saidcharge storage section to said second terminal of said battery inresponse to an increase in electrical current flowing through said fusemeans from a first end of said fuse means to a second end of said fusemeans; means enclosed within said case for electrically connecting saidfirst end of said fuse means to said second pole of said charge storagesection; and switch means enclosed within said case, said switch meansbeing configured to electrically connect said second end of said fuselink to ground in response to perturbation of said vehicle by anaccident; whereby in response to said perturbation by an accident saidswitch means electrically connects said second end of said fuse means toground so as to increase said flow of current through said fuse means,and said fuse means interrupts said flow of current from said secondpole of said charge storage section to said second terminal of saidbattery in response to said increased flow of current through said :usemeans.
 2. The battery of claim i, wherein said switch means isconfigured to electrically connect said second end of said fuse means tosaid grounded first terminal of said battery in response to perturbationof said vehicle by an accident.
 3. The battery of claim 2, wherein saidfirst pole of said charge storage section is the negative pole of saidcharge storage section is the positive pole of said charge storagesection.
 4. The battery of claim 2, wherein said fuse means comprises afuse link having a first end electrically connected to said second poleof said charge storage section and a second end electrically connectedto said second terminal of said battery, said fuse link being configuredto permit said flow of current therethrough under normal conditions andto interrupt said flow of current therethrough in response to anincrease in said flow of current flow.
 5. The battery of claim 4,wherein said switch means comprises:a first switch for connecting saidsecond end of said fuse link to ground in response to an impact receivedin a generally longitudinal direction by said vehicle; a second switchfor connecting said second end of said fuse link to ground in responseto an impact received in a generally lateral direction by said vehicle;and a third switch for connecting said second end of said fuse link toground in response to inversion of said vehicle.
 6. The battery of claim5, wherein said first switch comprises,a portion of said insulating casehaving a first substantially horizontal bore therein, said bore havingits axis aligned in a longitudinal direction with respect to a normaldirection of motion of said vehicle when said circuit breaker is mountedon said battery; first and second electrical contacts protruding intosaid bore to form a gap between said contacts within said bore, saidfirst contact being electrically connected to said second end of saidfuse link and said second contact being electrically connected toground; at least one paramagnetic closing member disposed in said boreso that said closing member is free to move longitudinal)y in said bore,said closing member being configured so that said closing memberelectrically closes said gap in the event that said closing member movesinto contact with said first and second contacts; and at least onemagnet means mounted in said bore for retaining said paramagneticclosing member at a spaced distance from said gap under normalconditions, and for releasing said closing member to move along saidbore into contact with said first and second contacts in response to animpact imparted to said vehicle in a selected longitudinal direction. 7.The battery of claim 6, wherein said paramagnetic closing member is aferrous ball, and wherein said magnet means is a magnetic cup having aconcave inner surface adapted to receive said ferrous ball.
 8. Thebattery of claim 7, wherein said third switch comprises:portion of saidinsulating casing having a vertically elongate chamber therein; firstand second electrical contacts mounted in said vertically elongatechamber so as to form a gap between said first and second contacts insaid chamber, said first contact in said chamber being electricallyconnected to said second end of said fuse link and said second contactin said chamber being electrically connected to ground; a ferrous balldisposed in said vertically elongate chamber so that said ferrous ballin said chamber is free to move vertically therein, said ferrous ball insaid chamber further being configured so that said closing memberelectrically closes said gap between said first and second contacts insaid chamber in the event that said ferrous ball in said chamber movesinto contact therewith; and a magnetic cup mounted in said chamber forretaining said ferrous ball in said chamber a spaced distance insubstantially vertical alignment below said contact gap in said chamberunder normal conditions, and for releasing said ferrous ball in saidchamber to move vertically into contact with said first and secondcontacts in said chamber in response to inversion of said vehicle by anaccident.
 9. The battery of claim 8, wherein said second switchcomprises:portion of said insulating case having a second substantiallyhorizontal bore therein, said second bore having first and second endsand having its axis aligned in a lateral direction with respect to anormal direction of motion of said vehicle when said circuit breaker ismounted on said battery; first and second electrical contacts mounted insaid lateral bore so as to form an electrical gap across said lateralbore at a location intermediate said first and second ends thereof, saidfirst contact in said lateral bore being electrically connected to saidsecond end of said fuse link and said second contact in said lateralbore being electrically connected to ground; a first ferrous balldisposed in said lateral bore intermediate said first end of saidlateral bore and said gap across said lateral bore so that said firstferrous ball in said lateral bore is free to move axially therein, saidfirst ferrous ball in said lateral bore being configured so that saidfirst ferrous ball electrically closes said contact gap across saidlateral bore in the event that said first ferrous ba)1 in said lateralbore moves into contact with said first and second contacts in saidlateral bore; a second ferrous hall disposed in said lateral boreintermediate said second end of said lateral bore and said gap acrosssaid lateral bore so that said second ferrous ball in said lateral boreis free to move axially therein, said second ferrous ball in saidlateral bore being configured so that said second ferrous ballelectrically closes said electrical gap across said lateral bore in theevent that said second ferrous ball in said lateral bore moves intocontact with said first and second contacts in said lateral bore; afirst magnetic cup mounted in said first end of said lateral bore forretaining said first ferrous ball in said lateral bore at a spaceddistance from said contact gap in said lateral bore under normalconditions, and for releasing said first ferrous ball in said lateralbore to move into contact with said first and second contacts in saidlateral bore in response to an impact imparted to said vehicle in afirst lateral direction by an accident; and a second magnetic cupmounted in said second end of said lateral bore for retaining saidsecond ferrous ball in said lateral bore at a spaced distance :rom saidcontact gap in said lateral bore under normal conditions, and forreleasing said second ferrous ball in said lateral bore to move intocontact with said first and second contacts in said lateral bore inresponse to an impact imparted to said vehicle in a second lateraldirection by an accident.
 10. The battery of claim 4, wherein saidswitch means comprisesa chamber having a lower portion with asubstantially circular rim about an edge thereof and a substantiallyclosed upper portion; first and second electrical contact rings mountedsubstantially circumferentially about said circular rim of said chamberso as to form a gap between said first and second contact rings, saidfirst contact ring being electrically connected to said second end ofsaid fuse link and said second contact ring being electrically connectedto ground; a ferrous ball disposed in said chamber so that said ferrousball is free to move about said chamber, said ferrous ball beingconfigured so that said ferrous ball electrically closes said electricalgap in the event that said ferrous ball moves into contact with saidfirst and second contact rings; and a magnetic cup mounted to saidchamber proximate the center of said lower portion for retaining saidferrous ball at a spaced distance from said gap under normal conditions,and for releasing said ferrous ball to move through said chamber andinto contact with said first and second contact rings in response tosaid perturbation of said vehicle by an accident.
 11. The battery ofclaim 10, wherein said chamber is a substantially hemispherical chamberhaving a bowl-shaped lower portion, and said first and second contactrings are mounted circumferentially about an upper edge of saidbowl-shape lower portion.
 12. The battery of claim 11, furthercomprising a magnetic belt mounted circumferentially about said upperedge of said bowl-shaped portion for retaining said ferrous ball in saidcontact with said first and second contact rings, said magnetic belthaving an inner surface to which said first and second contact rings aremounted.